I'm just throwing something out here to see if anyone has a take on my idea. I have a 3600 with 8 lugs. I would like to upgrade to discs but I ran into a snag. Nobody makes parts for it! It looks like to me that a late model disc (99 and up)should slip right over the hub and it is just a matter of fabricating some brackets for the caliper. The only problem I forsee is with the roller bearings. I don't know how well they will hold up and the only company that makes them is Federal Mogul. There isn't any Timken upgrades like the 1/2 tons have, so OEM is it. There is a rear disc kit out there from Street Rod Manufacturing, but who wants rear discs and front drums?